president obama took a break and visited the hoover dam. mitt romney took time out for a buritto bowl. and romney may have gotten zinger help from an unlikely ally today. vice president joe biden campaigning in north carolina. >> how they can justify raising taxes in the middle class has been buried the last four years. how in lord's name can they justify it? >> reporter: republicans pounced. >> we agreed. we need to elect mitt romney the next president of the united states. >> reporter: in person absentee voting is already under way. early voeting going only in other states. both sides know tomorrow's debate could be the last one some voters see. >> i think it's an opportunity for governor romney to flush out these issues face-to-face. >> he's very good at explaining what's going on, what he's proposing, what he has done. and i don't think there's anything to worry about. >> reporter: or does he? the latest poll shows the head-to-head race tightening a bit with president obama still on top. but on a key issue of the economy, a potentially